Cisco Technology, Inc.

Cisco Systems Wireless Networking (australia) Pty Limited

Alex C K Lam

Andrew Frederick Myles

David S Goodall

Donald J Miller

Brian Donald Hart

David Sheldon Stephenson

Mark Krischer

Richard Kinder

A method for automatic hidden node detection that includes observing frame exchange sequences that conform to a MAC standard such as the IEEE 802.11 standard. The method includes detecting a hidden node upon receiving a response frame without previously receiving the frame causing the response. Similar conclusions may be drawn from longer frame sequences. When a hidden node has been detected with reasonable certainty, a hidden node report is sent to a hidden node manager. In one embodiment, the hidden node manager is centralized, and in another, the management function is performed in a distributed manner. Upon receiving a report, the hidden node manager automatically invokes hidden node avoidance measures by sending one or more action frames. In another embodiment, the hidden node manager turns on a hidden node mitigation method. In the case of the IEEE 802.11 standard, the hidden node manager turns on the IEEE 802.11 hidden node mitigation method based on RTS/CTS exchange.

Detecting, reporting and mitigating hidden stations in a wireless data network

A method, apparatus, and software containing computer readable code to implement the method implemented in a first wireless device, e.g., an access point. The method includes, for a particular network identifier, e.g., BSSID, of at least one network identifier supported by the first wireless device that including a transmitter and modulator, each network identifier identifying a wireless network, e.g., an IEEE 802.11 BSS for which the first wireless device acts as an access point, transmitting full parent beacon frames periodically at the beacon frame rate for the particular network identifier; and transmitting at least one mini-beacon frames in between consecutive full parent beacon frames for the particular network identifier. Each mini beacon frame includes a subset of the information in a full parent beacon frame, and further including timing information indicative of when the next full parent beacon frame will be transmitted for the particular network identifier.

Using mini-beacons in a wireless network

A method and apparatus for synchronizing a local clock value in a wireless receiver receiving a data unit containing synchronization information. The method includes receiving a first data unit containing synchronization information, extracting the synchronization information from the received first data unit, copying a local free-running clock at a known reference point in time relative to the time the first data unit was received to generate a local timestamp; and calculating an offset to the free-running clock using the extracted synchronization information and the local timestamp, the calculating in non real-time, such that the sum of the calculated offset and the value of the free-running clock provides a local clock value that is approximately synchronized in time. The apparatus implementing the method is part of a node of a wireless station, and provides a time synchronization function, typically at the MAC layer.

Method and apparatus for clock synchronization in a wireless network

A method, apparatus, and software containing computer readable code to implement the method implemented in a first wireless device. The method includes, for a particular network identifier active in a wireless network, transmitting frames configured to advertise the infrastructure network of the particular network identifier. The transmitting of off-channel beacons is in a provided channel different than the channel in which the access point of the infrastructure wireless of the particular network identifier transmits beacon frames. The transmitting of off-channel beacons further is at a rate higher than the beacon rate frame at which the access point of the infrastructure wireless of the particular network identifier transmits beacon frames.

Off-channel beacons in a wireless network

A method, an apparatus and a carrier medium storing instructions to implement the method. The method is in a first wireless station of a wireless network, and includes wirelessly receiving a signal corresponding to a packet wirelessly transmitted by a second wireless station. The packet includes a subpacket and a check sequence. The method further includes verifying the integrity of the subpacket, the verifying at least using the check sequence. The method further includes, in the case that the subpacket fails the verifying, reducing the power consumption of at least one component in the first wireless station for a time interval.

System and method for saving power in a wireless network by reducing power to a wireless station for a time interval if a received packet fails an integrity check

Detecting, reporting and mitigating hidden nodes in a wireless data network

A MAC controller for a station in a wireless network, and a method for transmitting packets according to a wireless network MAC protocol. A MAC controller includes a packet scheduler connected to an interface for providing packets for transmission, and transmit hardware connected to a physical layer interface of the station to execute sub-sequences. The transmit hardware includes a buffer to receive from the scheduler and store a set of execution data, and also a signal path to the scheduling engine to provide an indication to the packet scheduler of the outcome of a sub-sequence. The transmit hardware is connected to a receiver to indicate the reception at the wireless station of a data unit that may be a response to a transmission of a sub-sequence.

Method and apparatus using pipelined execution data sets for processing transmission frame sequences conforming to a wireless network MAC protocol

Disclosed herein are a method, an apparatus, and a carrier medium including one or more computer readable code segments to instruct one or more processors of a processing system to implement a method. The method is in a first wireless station of a wireless network. The method comprises generating a check sequence to protect the integrity of a subpacket of a packet, wherein the packet is to be wirelessly transmitted. The method further comprises embedding the check sequence in an embedding field within the packet. The embedding field is located prior to the end of the subpacket. The method further comprises wirelessly transmitting the packet. The check sequence is generated such that a second wireless station wirelessly receiving a signal corresponding to the packet can sequentially verify the integrity of the subpacket as if the check sequence were appended at the end of the subpacket being protected.

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Chatswood, Australia

Alex C K Lam